package org.smart4j.chapter2.helper;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.smart4j.chapter2.util.CollectionUtil;
import org.smart4j.chapter2.util.PropsUtil;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Properties;

/**
 * 数据库操作助手类
 */
public final class DatabaseHelper2 {

    private static final Logger LOGGER = LoggerFactory.getLogger(DatabaseHelper2.class);
    private static final QueryRunner QUERY_RUNNER = new QueryRunner();
    private static final ThreadLocal<Connection> CONNECTION_HOLDER = new ThreadLocal<Connection>();//线程安全

    private static final String DRIVER;
    private static final String URL;
    private static final String USERNAME;
    private static final String PASSWORD;

    static {
        Properties conf = PropsUtil.loadProps("config.properties");
        DRIVER = conf.getProperty("jdbc.driver");
        URL = conf.getProperty("jdbc.url");
        USERNAME = conf.getProperty("jdbc.username");
        PASSWORD = conf.getProperty("jdbc.password");

        try {
            Class.forName(DRIVER);
        } catch (Exception e) {
            LOGGER.error("can not load jdbc driver", e);
        }
    }

    // 获取数据库连接
    public static Connection getConnection() {
        Connection conn = CONNECTION_HOLDER.get();
        try {
            conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
        } catch (Exception e) {
            LOGGER.error("get connection failure", e);
        } finally {
            CONNECTION_HOLDER.set(conn);
        }
        return conn;
    }

    //    关闭数据库连接
    public static void closeConnection() {
        Connection conn = CONNECTION_HOLDER.get();
        if (conn != null) {
            try {
                conn.close();
            } catch (Exception e) {
                LOGGER.error("close connection failure", e);
                throw new RuntimeException(e);
            } finally {
                CONNECTION_HOLDER.remove();
            }
        }
    }

    //    查询实体列表
    public static <T> List<T> queryEntityList(Class<T> entityClass, String sql, Object... params) {
        List<T> entityList;
        try {
            Connection conn = getConnection();
            entityList = QUERY_RUNNER.query(conn, sql, new BeanListHandler<T>(entityClass), params);
        } catch (Exception e) {
            LOGGER.error("query entity list failure", e);
            throw new RuntimeException(e);
        } finally {
            closeConnection();
        }
        return entityList;
    }

    //    查询实体
    public static <T> T queryEntity(Class<T> entityClass, String sql, Object... params) {
        T entity;
        try {
            Connection conn = getConnection();
            entity = QUERY_RUNNER.query(conn, sql, new BeanHandler<T>(entityClass), params);
        } catch (Exception e) {
            LOGGER.error("query entity failure", e);
            throw new RuntimeException(e);
        } finally {
            closeConnection();
        }
        return entity;
    }

    //    多表查询
    public static List<Map<String, Object>> executeQuery(String sql, Object... params) {
        List<Map<String, Object>> result;
        try {
            Connection conn = getConnection();
            result = QUERY_RUNNER.query(conn, sql, new MapListHandler(), params);
        } catch (Exception e) {
            LOGGER.error("execute query failure", e);
            throw new RuntimeException(e);
        }
        return result;
    }
//    执行更新语句（包括update,insert,delete）
    public static  int executeUpdate(String sql,Object...params){
        int rows=0;
        try{
            Connection conn=getConnection();
            rows=QUERY_RUNNER.update(conn,sql,params);
        } catch (SQLException e){
            LOGGER.error("execute update failure",e);
            throw new RuntimeException(e);
        } finally {
            closeConnection();
        }
        return rows;
    }
//    插入实体
    public static <T> boolean insertEntity(Class<T> entityClass,Map<String,Object> fieldMap){
        if(CollectionUtil.isEmpty(fieldMap)){
            LOGGER.error("can not insert entity:fieldMap is empty");
            return false;
        }
        String sql="insert into "+getTableName(entityClass);
        StringBuilder columns=new StringBuilder("(");
        StringBuilder values=new StringBuilder("(");
        for(String fieldName:fieldMap.keySet()){
            columns.append(fieldName).append(", ");
            values.append("?, ");
        }
        columns.replace(columns.lastIndexOf(","),columns.length(),")");
        values.replace(values.lastIndexOf(","),values.length(),")");
        sql += columns+" VALUES "+values;
        Object[] params=fieldMap.values().toArray();
        return executeUpdate(sql,params)==1;
    }
//    更新实体
    public static <T> boolean updateEntity(Class<T> entityClass,long id,Map<String,Object> fieldMap){
        if(CollectionUtil.isEmpty(fieldMap)){
            LOGGER.error("can not update entity:fieldMap is empty");
            return false;
        }
        String sql="update "+getTableName(entityClass)+" set ";
        StringBuilder columns=new StringBuilder();
        for(String fieldName:fieldMap.keySet()){
            columns.append(fieldName).append("-?, ");
        }
        sql += columns.substring(0,columns.lastIndexOf(", "))+" where id=?";
        List<Object> paramList=new ArrayList<Object>();
        paramList.addAll(fieldMap.values());
        paramList.add(id);
        Object[] params=paramList.toArray();
        return executeUpdate(sql,params)==1;
    }
//    删除实体
    public static <T> boolean deleteEntity(Class<T> entityClass,long id){
        String sql="Delete from "+getTableName(entityClass)+" where id=?";
        return executeUpdate(sql,id)==1;
    }
    private static  String getTableName(Class<?> entityClass){
        return entityClass.getSimpleName();
    }
}
